Creating a Windows Server 2025 Hyper-V Cluster

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This guide walks through configuring a highly available Hyper-V cluster on Windows Server 2025 using shared iSCSI storage.

Step 1 — Install the Hyper-V Role (on Domain-Joined Servers)

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Ensure both servers are joined to your Active Directory domain before proceeding.

Server 1 Configuration

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1. Install the Failover Clustering feature.
2. Configure shared storage via iSCSI Initiator.
3. Bring disks online on Server 1 and create new volumes with appropriate drive letters.
4. Create an External vSwitch in Hyper-V Manager for VM traffic.

Server 2 Configuration

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1. Install the Failover Clustering feature.
2. Connect to the shared storage via iSCSI Initiator.
   • The disks will appear offline — leave them that way.
3. Create an External vSwitch with the exact same name as on Server 1.

Step 2 — Validate the Cluster Before Creation

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1. On Server 1, open Failover Cluster Manager.
2. Under Management, select Validate Configuration.
3. Add all intended cluster nodes.
4. Choose Run All Tests → Next.
5. Review the report and resolve any warnings or errors.
   • Skipping validation may void Microsoft support.

Step 3 — Create the Cluster

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1. In Failover Cluster Manager, select Create Cluster.
2. Add all node names.
3. Name the cluster (e.g., 2025Cluster).
4. Assign a Cluster IP Address on the production network.
5. (Optional) Keep “Add all eligible storage to the cluster” checked.
   • Any attached LUNs will be added as Cluster Disks, with one chosen for quorum.
6. Click Next and wait for the cluster to be created and load in Failover Cluster Manager.

Step 4 — Validate Cluster Creation

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Storage Validation

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• Confirm disks under Storage > Disks.

Network Validation

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1. Identify and rename cluster networks as needed:
   • Heartbeat Network → uncheck “Allow clients to connect through this network”.
   • Storage Network → select “Do not allow cluster communication on this network”.
   • Production Network → enable both “Allow cluster network communication” and “Allow clients to connect through this network.”

Step 5 — Configure Cluster Shared Volumes (CSV)

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1. Go to Storage > Disks.
2. For any disk marked Available Storage, right-click → Add to Clustered Shared Volumes.
3. Confirm disks now appear under Cluster Shared Volumes.

Step 6 — Adjust Hyper-V Storage Paths (Server 1)

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1. Open Hyper-V Manager → Hyper-V Settings.
2. Under Virtual Hard Disks, click Browse:
   • Navigate to /ClusterStorage/Volume1/
   • Create folder VHDX
   • Save path as /ClusterStorage/Volume1/VHDX
3. Under Virtual Machines, click Browse:
   • Navigate to /ClusterStorage/Volume1/
   • Create folder VMConfigFiles
   • Save path as /ClusterStorage/Volume1/VMConfigFiles
4. Apply and save changes.

Step 7 — Mirror Storage Settings on Server 2

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1. In Hyper-V Manager, right-click → Connect to Server → select the second node.
2. Open Hyper-V Settings.
3. Update default paths for:
   • Virtual Hard Disks → /ClusterStorage/Volume1/VHDX
   • Virtual Machines → /ClusterStorage/Volume1/VMConfigFiles
4. Repeat these steps for all nodes.

Step 8 — Create a Clustered Virtual Machine

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1. In Failover Cluster Manager, right-click Roles → New Virtual Machine.
2. Select the target node for creation.
3. Complete the wizard.
4. The VM will now appear under Roles — fully managed by the cluster.

Success!

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You’ve successfully configured a Windows Server 2025 Hyper-V Cluster with shared iSCSI storage and failover protection.

Tip: Regularly run Validate Cluster and back up your cluster configuration XML for quick recovery.